Reverse transcription-polymerase chain reaction on pooled samples to detect bovine viral diarrhea virus by using fresh ear-notch-sample supernatants.

Ear-notch samples from 3,599 yearling heifers were collected to detect persistently infected (PI) animals with suspect bovine viral diarrhea virus (BVDV). Individual immunohistochemistry (IHC), individual antigen-capture enzyme-linked immmunosorbent assay (AC-ELISA), and reverse transcription-polymerase chain reaction (RT-PCR) tests with pooled ear-notch supernatants were compared with samples from 3,016 heifers, whereas RT-PCR ear-notch pools and individual AC-ELISA tests were compared with samples from all 3,599 heifers. Four heifers were identified positive by both IHC and AC-ELISA, whereas the remaining heifers were identified negative by both tests.

Calving and calving management of beef cows and heifers on cow-calf operations in the United States.

A national sample of cow-calf producers was contacted to participate in a study to describe selected calving management practices on operations throughout the United States. Information was gathered on calving season, frequency of dystocia, frequency of observation, timing of assistance, and calving facilities. Regional and herd size differences existed in all parameters evaluated.

Percutaneous collection of fetal fluids for detection of bovine viral diarrhea virus infection in cattle.

Objective: To develop a method for percutaneous collection of fetal fluid from cattle in the late stages of gestation and determine whether bovine viral diarrhea virus (BVDV) can be isolated from such fluids.

Design: Case series.

Animals: 169 pregnant beef cattle.